3M 2273E - Manual (Page 14)

Using Current Indications During Locating
Both the Transmitter and Receiver will indicate cable current. These
current indications will help to select a trace frequency, identify the correct
cable and trouble shoot the set up.
When using the direct connect method, the Transmitter output current
number is displayed. A "LO" display, or number less than 50, indicates a
weak tracing signal. A number higher than 70 represents a strong tracing
signal. When the Receiver is used to find the cable near the Transmitter
connection point, the current number displayed in the Receiver should
correspond (within 5 points) to the Transmitter number: IF you are over the
correct cable, AND most of the signal is flowing in that cable.
Note: On the Transmitter every ten units on the current display represents
a factor of two in current magnitude. On the Receiver, trace current
readings for the additional auxiliary frequencies (except LF) are displayed
in milliamps. For all other trace frequencies every ten units on the Current
display represents a factor of two in current magnitude.
When the Transmitter signal is applied using the Dyna-Coupler, the
Transmitter current display indicates the current in the coupler and not in
the cable. In order to get a measure of the cable current, point the Receiver
at the exposed cable about one meter from the Dyna-Coupler. This will be
the current number that should be used to identify the correct cable.
Page 13
DETERMINING CABLE DEPTH AND CURRENT
Place the Receiver Antenna on the ground directly above the cable with
the handle parallel to the path. Press
and the display will indicate
the cable depth and relative current . Current is displayed in the lower
left corner of the display. Press twice to continue tracing. You may
also press to return to Trace mode.
Note: During a depth-current measurement, the display will exhibit
' – – – ' when the received signal is too low, too high, or erratic.